L99/SS Engine ticking, clanging noise? Lifters, evap, exhaust?.

[Texamaro]

2011 SS Camaro 6.2 L99.
Car has been running perfectly but I was getting some noise from driveshaft support bearing. I jacked it up and replaced it and problem solved. However I noticed on my first time driving after what sounded like an engine ticking noise. I brought it back home and thought perhaps exhaust leak since I had to drop the exhaust when working on the driveshaft. I have a magnaflow exhaust on stock exhaust manifolds so I only had to take it off the hangers and remove 4 nuts to slide of the connecting collars. I made sure everything was tight but no difference. I tried to trace the noise and it sounds like it is from the engine bay close to front of engine (possibly passenger side/front). I removed serpentine and ac belts and ran the car for 30 seconds to see it it could be a pulley but the noise was identical. Replaced belts and after doing some research saw that lifter issues are a common issue and can get stuck or frozen. I removed passenger side valve cover and all rocker arms were moving properly. No excessive space or noise on lifters that I could tell so I put the cover back on. I also read that evap solenoid issues could cause ticking. I have had 1 code for a couple days p0455 evap code (but have driven some miles on it without any noise) so I decided to resolve that and possibly it would fix the ticking. Replaced my evap purge valve/solenoid in the engine bay and cleared the code which doesn't appear to be returning after several minutes of running but the ticking is still there.
I'm at a loss and have tried everything I can think of.

Here's a link to a video my friend took last night. I started it and revved to maybe 2k in the video.
https://youtu.be/NEgFU979vGM

[InFiD3ViL]

Wow. That doesn't sound good at all.

I haven't heard anything like that before. No misfire codes? I would pull the covers again and get a good look at every spring for possible crack. It is almost a scraping kind of sound.

[Texamaro]

Originally Posted by InFiD3ViL

Wow. That doesn't sound good at all.

I haven't heard anything like that before. No misfire codes? I would pull the covers again and get a good look at every spring for possible crack. It is almost a scraping kind of sound.

No misfire codes. The only code was the evap code I listed above. I have a friend of a friend that is a mechanic at local Chevrolet dealership and he said he will look if I can't figure it out in a few days.

[InFiD3ViL]

Originally Posted by Texamaro

No misfire codes. The only code was the evap code I listed above. I have a friend of a friend that is a mechanic at local Chevrolet dealership and he said he will look if I can't figure it out in a few days.

I would not run it until then, or at least at a minimum. Because if it is internal, the more you run it the worse it's going to get. I know it's hard because you want to locate the issue, but I would hate for this to go catastrophic.

Please update the thread when you get more information. Good luck man. I know this car be very stressful.

[Texamaro]

Originally Posted by InFiD3ViL

I would not run it until then, or at least at a minimum. Because if it is internal, the more you run it the worse it's going to get. I know it's hard because you want to locate the issue, but I would hate for this to go catastrophic.

Please update the thread when you get more information. Good luck man. I know this car be very stressful.

That makes sense to not start or and run it anymore at this point and is the route I'm going to go for this point in time. It may be a few days before the mechanic can come take a look but I'll post updates here. Thanks for the input!

[Black_SS10]

What does the oil look like? Any metal?

Could be a broken valve spring.

[Texamaro]

Originally Posted by Black_SS10

What does the oil look like? Any metal?

Could be a broken valve spring.

I haven't changed the oil since the noise started, but couldn't see any metal or bad discoloration on the stick, or when I took off the valve cover. Perhaps good idea to drain and change oil and see what happens.

[Black_SS10]

Originally Posted by Texamaro

I haven't changed the oil since the noise started, but couldn't see any metal or bad discoloration on the stick, or when I took off the valve cover. Perhaps good idea to drain and change oil and see what happens.

I would start with draining the oil. Cut the filter and look for metal. Sorry, I missed where you said in your original post that you took the valve cover off, may want to do the same on the opposite side. You stated everything was moving properly? Did you run the engine when you checked? With the engine off did you check each rocker and spring by hand? Could be a couple different things or a combination of things. Shitty situation.

[xstuntman]

I'd pull the plugs for a quick look.

[pnwdan]

Might be lifter bouncing around? I would pull the valve covers also. See if you have a bent push rod or your rocker trunions gave out letting up on the pressure applied to the lifter. The OEM rockers are a known weak point.

[InFiD3ViL]

I am hoping that someone that has heard a sound like this will be able to point you in the right direction. It doesn't sound like what I am used to hearing from a bad lifter, but that really means nothing as no failure is identical.

Its a strange sound. It sounds like a scraping sound but if you turn up the volume with headphones it also sounds like an airflow 'chuffing' sound, for lack of better words. It may just be my imagination, but the engine doesn't sound healthy when it was revved. Like it was missing.

Texamaro, is your AFM still enabled or was it tuned out? Not that it really matters if a lifter or AFM lifter failed, but just trying to get a better idea of the state of the engine before the issue occurred.

[Welker2]

Have heard that sound before (or one very similar) .. it turned out to be a bad lifter. Regardless, I would definitely not be running it again until it can be fully checked out; I especially would not be revving the engine at this point as you are very likely to cause even more damage then already has been.

[Greenhornet2]

Sounds like valvetrain. I'd pull the cover. Then turn the engine over until each cylinder comes to TDC then see if there is any play in the rocker. Trunion bearings might have spit out sounds a bit like rubbing. Should be able to tell. Might need to loosen the rockers to inspect more thoroughly if you can't tell right away.

[Aqua Blue RS/SS]

Originally Posted by Greenhornet2

Sounds like valvetrain. I'd pull the cover. Then turn the engine over until each cylinder comes to TDC then see if there is any play in the rocker. Trunion bearings might have spit out sounds a bit like rubbing. Should be able to tell. Might need to loosen the rockers to inspect more thoroughly if you can't tell right away.

I agree with this. Valve train is my guess. I’d definitely be pulling the valve covers, based on the sound worst case might be a lifter spun or one that isn’t holding pressure. Slightly better case is probably a trunnion bearing or something like that. It almost sounds like it’s kind of random but definitely speed related, ie. A rod knock is steady and predictable, this sounds like it comes and goes in severity but never totally goes away. don’t sound like a bottom end problem to me. One of the only Sucky parts about the ls motors is to get to the lifters you have to pull the heads.